Operation of open-hearth furnaces



Oct. 16, 1928. 1,687,682

F. B. M KUNE OPERATION OF OPEN'HEARTH FURNACES Filed May 5. 1922 5 Sheets-Sheet 2 Owls, 1928. 1,687,682

F. B. McKUNE OPERATION OF OPEN HEARTH FURNACES Filed May 5. 1922 3 Sheets-Sheet 3 Patented Oct. 16, 1928.

UNITED STATES PATENT OFFICE,

FRANK B. MCKUNE, or HAMILTON, ONTARIO, CAuAnA, ASSIGNOR, BY MESNE ASSIGN- MENTS, 'ro OPEN-HEARTH COMBUSTION COMPANY. or CHICAGO, ILLINOIS, A con- PORATION OF DELAWARE.

Application filed May 5,

This invention, which relates generally, to improvements in the operation of open hearth furnaces, more particularly has for its object to provide certain improved methods of operation of furnaces having improved structural arrangements, especiallyadapted for the economical burning of gases, a more uniform distribution thereof and for. lengthening the life of the furnace and the checker work that constitutes a part thereof. v

Another and essential object of my in-. vention is to provide in open hearth furnace operation methods, certain improved features adapted'for increasing the rapid melting of the heat and which give absolute control of the flame in such furnace, with a material productive increase over the method generally utilized for heating furnaces.

With other objects in view, my invention, in its subordinate features, embodies certain improvements in the operation of the damper rigging that controls the air induction and eduction and in such manner that little or no gas is lost, when reversing the will be best understood by referring to the accompanying drawings which illustrate a preferred form of my invention, it being premised, however, that various changes in the details or modifications of the cooperativearrangement and utilization of the parts shown may be readily made without departing from the spirit and the scope of my inventionas defined in the appended claims. In the drawings Figure 1 is a horizontal section of an open hearth furnace embodying my invention, the damper operating mechanism at both ends being shown in plan viewfthe damper at one end (the inlet) being shown as partly closed and the damper atthe other end (the outlet) being shown as wholly opened;

Figure 2 is a vertical longitudinal section thereof, on the line 2-2 on Figure 1;

Figure 3" is a partly vertical section and partly end elevation of the furnace and 1922 Serial No. 558,755.

the damper rigging mechanism, hereinafter spec fically referred to;

Figure 4 is a horizontal section of one end of the furnace taken substantially on the l1nef1-4 on Figure 3; and

Figure 5 is a detail sectional view of one of-the control valves or dampers, and the hydraulic cylinders and lever connections cooperatively joined therewith, the latter being in side elevation.

In the drawings, I have illustrated a conventional form of open hearth furnace in which is embodied my invention and in the showmg'thereof, see particularly Figures 1 and 2, 11.desig nate the usual wet or dry ports, one at each end, into which the gases are delivered in any suitable manner, prefthrough the jet outlets 2020,' with the gas ports 1-1 and which connect, at their outer ends, with the supply branches 30 3O that join with the main laterals or gas pipes 3131, which in turn, connect with the main supply pipes 3 in the manner clearly shown-in Figures 1 and 3 of the drawings.

The gas ports 1l, before referred to, communicate with the main air passages 10 1O and, when the supplemental air passages 44, presently again referred to, are closed, the entire air can be put through the inlet port l, while if partly closed, part of the air will pass through inlet 1 and part above and around such inlet, and such air can be either forced or natural air.

By referring now more particularly to Figures 1 and 4, it will be observed that a supplemental air passage 44 is located at each side of the gas ports 1-1 and their air ports 1010, it being understood that the arrangement of the gas, the main air ports, the supplemental air ports,and the comprised in my construction of open hearth furnace, are included hydraulic damper rigging devices, which, per se, constitute an essential feature of my invention.

As is best shown in Figures 1 and 2, the

' tance beyond the end walls .to provide rest portions on which the doors 7-7 are received, when shifted to the open position, as indicated at the left of Figure 2.

Eachdamper or cut off door 7 is p'rovlded with an outwardly extended member 70 and each of the members 70 has a slotway 71 into which is received the lower end of a lever 12 secured at the upper end on a shaft 13 that is journaled in suitable bearing brackets 14-44 attached to and projected from the end Walls of the furnace.

The shaft 13, midway its length, has a crank member hereinafter termed the cylinder lever 15, with which joins a vertically reciprocable shaft 16 that connects with the pistons of a pair of hydraulic cylinders 17-17, suitably mounted over the outer face.

of each end wall and which include the alterv nately operating intake and outlet pipes 18,

are connected up n any 1y for which, in practice, well known manner with a fluid sup actuating the cylinder pistons for s 'lfting the dampers 7-7, at predetermined times,-

for reversing the furnace.

While I have specifically mentioned-11y draulic cylinders for actuating'the devices that shift the dampers to the I whollyor partly open or closed positions, it is to understood that the operation-of the dampers or doors 4-4 can be done by hydraulic steam, electricity or compressed'air with the I changed without stopping the furnace and the cost ofirepairsis. very' much less than is control of the same absolutely under the furnace operator. 7

4O designate cooling pipes that enter through the sides of the furnace adjacent the gas tunnels. a

From the foregoing description taken in connection with the drawings, the complete arrangement, the manner ofcusing and the advantages of my invention will be. readily apparent to those familiar with the operation or use of furnaces of the typereferr'ed-toq;

It is to be understood that while the-entire alr can be directed through thepassages to the gas ports 1-1, yet in the present case.

it is desired that a portion of the air go over the top,'and it is only 'a matter of opening the dampers at the inlet end to any desired degree, depending upon the amount of air that may be desired or going over the top of the furnace, it being readily apparent by referring to the drawings that, when the liqui thepassages over the arched top through which the gas ports pass and are discharged directly under the top of the hearth above and beside the central port.

To give the necessary area that may be desired, the dampers at the outgoing end of the furnace are ordinarily pulled open thelr entire length, as shown.

By controlling the air and gas supply in the manner stated, it increases the yield of the heat at least two per cent, due to get tingthe air thoroughly mixed with the gases before heating the metal.

With the dampers, before referred to, arranged as shown and described, it is possible to effectively control the velocity of air and gas entering the furnace and also to burn through one single port, any gas,'and at the same time have full area on the outgoing end of the furnace.

Furthermore, in my construction'of open hearth furnace, a higher eificiency of the gases is obtained and perfect control in the directing of the gas into the furnace is also provided.

In my-improved furnace, it is made possible to work gases that could not, so far as I know, be controlled on the openhearth furnace due to their lightness'and lack of control of velocity.-

In the working of my construction of furnace, free a1r going into the-furnace except Theflow of gases in my "furnace can be usual in other types of like furnaces, due to the perfect control and complete combustion'ofthe-gases."- 1

Further, in myconstruction of furnace. it is possible to work in any combination of ,fuelor any two gases? at the same time. I Myjimprovements' may be readil'ywapplied to an o fthe conventional types of furnaces and, in building new furnaces, it would be only necessary to have-two re generators instead of four.

Furthermore, in the invention no gases are. lost in reversing the furnace and also very little dirt' carried down throughthe regenerators, due to the,

perfect combustion obtained fromlthe gases. Another and important advantage in the use of damper controlsarranged as shown practical use of my By having the dampers so that one can open them on the outgoing end of.the' furnace, by doing so gives the full area ofthe dampers and the stack, otherwise the draft on the furnace would be checked.

' In the use of my special arrangement of valve and damper mechanism, it brin s abouta great saving, when reversing t e valves as no gas .passes through the revefsing valves whatever. 1

The advantage of this feature of my invention will be apparent, when'it is under stoodthat 15% of the gas required togrun the furnace .is lost in the reversing of the furnace.

I claim. I

1. The method of metallurgical heating, which consists in mixing air with fuel, in troducing said mixture into a furnace chamher through a relatively constructed inlet, introducing additional air through another inlet, burning the fuel in the furnace and conducting the products of combustion from said furnace chamber through said inlets and additional areas together forming an outlet of greater area than the combined areas of said inlets.

' 2. The method of metallurgical heating, which consists in mixing air with fuel, introducing said. mixture into a furnace chamher at a relatively high'velocity through a relatively small inlet, introducing additional air through another inlet, decreasing the velocity of the fuel and air in the furnace chamber and conducting from said furnace chamber the products of combustion through said inlets and, additional area together form'ng' an outlet of substantially greater effective area than said inlets.

3. The method of metallurgical heating, which consists inmixing a1r with fuel, 1ntroducing said mixture into a furnace chamher at a relatively high velocity through a relatively small inlet, introducing additional air through another inlet, decreasing the velocity of the fuel and air in the furnace chamber and conducting the products of ditiqna-l as ducting th Isaidfchamber through a second set of pas- 8 combustion from said furnace chamber through said inlets at less velocity than the 5 air and fuel were introduced into the furnace chamber.

4. The method of metallurgical heating,

which consists in mixing air with fuel, introducing said mixture into a furnace chamber at a relatively high velocity through a relatively small inlet," introducing an additional selectively determined quanity of air through another inlet, decreasing the velocity of the fuel and air in the furnace chamberand conducting the products of combustion from said furnace chamber through said inlets at less velocity than the air and fuel were introduced into the furnace chamber. 5. The method of heating a reversing furnaceewh' ch conslsts in Introducing a mixture of air and fuel into a furnace chamber at rel- .atively high velocity through a assage of relatively; constricted area, intro ucin ad 'through another passage, urn- 1n the furnace chamber, con- .products of combustion from al f sages of relatively large total area, decreasing the total- ,eflective area of said second set of passages and increasing the total effective area of said first set of passages, introducin the mixture of air and fuel through one o said second set of, passages, introducing additional air through another of said passages, burning the fuel in the furnace chamber, and

conducting the products of combustion from said furnace chamber through said first set of passages.

6. The methodof heating a reversing furnace, which consists in introducing a mixture of air and fuel into a furnace chamber at relatively high velocity through a passage of relatively constricted area,-introducing additional air through another passage in a stream above the mixed air and fuel, burning said fuel in the furnace chamber, conducting,

the products of combustion from said chamher through a second setof passage's of rel atively large total area, decreasing the total effective area of said second set of passages and increasing the total effective area of said first set of passages,introducing the mixture 116" of air and fuel through one of said second set of passages, mtroducing addit onal fair through another of said passa-ges, burning the fuel in the furnace chamber, and conduct,

ing the products of combustion from said furnace chamber through said first set of f passages.

Signed at Hamilton, Ontario, this 21st day of April, 1922.

' FRANK B. MoKUNE. 

